1. Field of the Invention
This invention relates generally to surgical needles and, more particularly, to cutting edge and tapercut needles having a blunt tip for use in suturing cutaneous tissues of the body while at the same time decreasing potential skin penetration of the gloved hand of an operator.
2. Description of the Prior Art
In the design of surgical needles it is desirable for the needle to easily penetrate and smoothly pass through the tissue being sutured. The needle should be designed so as to minimize the resistance of the tissue to the passage of the entire needle through the tissue. The ease of penetration is dependent upon the sharpness of the needle point. Once the needle has penetrated the tissue, the body of the needle must be drawn through the opening in the tissue. This should be done with minimal force, and the needle should be shaped so that it will move smoothly through the opening. With cutting edge needles, widening of a hole made by initial penetration is effected by the cutting edge(s) as they slide through the tissue until there is a fully developed hole. Thus, in the design of surgical needles, it is desirable to make the cutting edge(s) and the point of the needle as sharp as possible.
Recently, another design criteria has surfaced as a result of the increasing awareness of the severity of contracting Human Immunodeficiency Virus (HIV) and Acquired Immune Deficiency Syndrome (AIDS) through accidental needle sticks. The members of professions that must deal on a daily basis with the risk of coming in contact with people that do or may have HIV or AIDS are acutely aware of the severity. These professionals are therefore taking every precaution to reduce the risks. Members of the medical profession, especially surgeons, are in an extremely high risk position when performing operations. The knowledge that infectious diseases such as the AIDS virus can spread by an accidentally inflicted needle stick from a contaminated needle administered to the person having AIDS is the cause for much concern.
Accordingly, there has been an increasing amount of activity in the area of surgical needle tip design. In order to decrease the potential transmission of the above infectious diseases where accidental needle stick is the means for such transmission, taper point surgical needles having a blunt tip have been developed. However, these needles have no cutting edges and enlarge a hole made by the point by pure blunt dilation with no cutting action whatsoever. For example, U.S. Pat. No. 5,123,190 to McIntosh discloses a taper needle which includes a needle tip having a blunt head. The blunt tip has a part spherical or other curved shape with no sharp edge surfaces. However, as with conventional taper point needles, the blunt needle disclosed in U.S. Pat. No. 5,123,190 does not having any cutting edges.
The design techniques that can be employed to meet the above criteria are in conflict. For example, to improve needle penetration the needle point should be made as sharp as possible. But by sharpening the needle point, the penetration force needed to penetrate the gloved hand of an operator is significantly decreased. Likewise, accidental skin penetration of the gloved hand can be reduced by making a less sharper point, but this will correspondingly increase the initial force required for penetration. Thus, the design of a needle with favorable performance in both areas requires tradeoffs to be made in the two criteria to arrive at a needle with optimal overall performance. Thus, there is a need to develop an improved surgical needle which significantly reduces the probability of skin penetration of the gloved hand of an operator while being adapted to suture cutaneous tissue of the body as well as other types of tissue.